George Bush cannot rely on the new Republican-controlled Senate to do everything he wants

FOR most of his first two years, the Democrat-run Senate was George Bush's biggest domestic headache. From tax cuts (which they refused to make permanent) to judicial appointments (where they held up the confirmations of conservatives), Senate Democrats used their tiny majority to stall Mr Bush's agenda and push their own priorities.

No longer. As of January 7th, when the 108th Congress convenes, the Senate will be back in Republican hands. Though the majority is slender (51 Republicans, 48 Democrats and one independent), the power-shift is big: the majority party controls everything from the legislative calendar to the chairmanship of committees. From next week, Mr Bush's political allies rather than his antagonists will be in charge. Does that mean a smooth ride for his domestic agenda?

History suggests caution. Not only is the majority razor-thin, but senators are a fiercely independent lot, often reluctant to do their president's bidding. Bill Clinton, for instance, had a rocky ride with a Democrat-controlled Congress between 1992 and 1994, famously failing to persuade lawmakers to pass his ambitious healthcare plan. Nonetheless, Mr Bush has several big advantages. First, many Republican lawmakers are all too aware that they owe their jobs to the president's popularity and his prodigious campaigning before November's election. Equally important, Bill Frist, the Senate's new majority leader (and hence top agenda-setter), is a certified Friend of George.

Mr Frist, a 50-year-old heart-surgeon-turned-senator from Tennessee, emerged victorious from the Republicans' December debacle, when their former leader in the Senate, Trent Lott, was forced to resign for suggesting America might have been better off had racial segregation continued. Elected by acclamation in an unprecedented telephone conference-call on December 23rd, Mr Frist is the party's new star: a telegenic, marathon-running over-achiever, who spends his holidays doing field surgery in the Sudan.

He is also extremely close to the White House. In the 2000 presidential campaign, Mr Frist was the Bush campaign's link to Senate Republicans. Both his style (informal and congenial) and his attitudes (staunch conservatism with no ideological edge) are much like Mr Bush's. He shares the president's domestic priorities, such as making the 2001 tax cut permanent and providing a prescription-drug benefit for old people.

Unfortunately, Mr Frist cannot simply ram these things through. With a majority too small to be filibuster-proof, he will need to work with Democrats, as well as forge compromises between the conservative and moderate wings of his own party. As one of the least seasoned senators to hold the top job (he has been in the Senate for only eight years), Mr Frist will have to rely on other top Republicans for guidance through the minefield of Senate procedural rules. His relative inexperience is also likely to strengthen the role of powerful committee chairmen.

Control of committee chairmanships is one of the principal means by which the majority party calls the shots in the Senate. For technical reasons, there may be a delay before the new men take over this year. Before he resigned, Mr Lott failed to reach agreement with Senate Democrats over funding and other organisational details of the Senate committee structure. Until a deal is reached, the old committee structure—with Democratic chairmen—remains in force.

They will be dislodged before long, however, and some of the new chairmen will undoubtedly make life easier for Mr Bush. Orrin Hatch, the ideological (though often reasonable) new boss of the Judiciary Committee, will make sure the logjam on judicial appointments is broken quickly. The new head of the Budget Committee, Don Nickles, is another staunch conservative who will push hard for more tax cuts. For the past two decades another Republican, Pete Domenici, was top Republican dog on the Budget Committee. Mr Domenici was more worried about deficits than tax cuts. Mr Nickles, in contrast, is widely seen as someone who regards the budget largely as a vehicle for lower taxes.

Chuck Grassley, the new head of the Finance Committee (the most important tax-writing body in the Senate) is more of a deal-maker than Mr Nickles. Though he will probably push the president's tax-cutting agenda, it will have his own populist touch. Mr Grassley, for instance, is keen on rules to stop American companies avoiding tax by incorporating abroad, a policy the White House is against.

Less obvious is whether the Bush team will be able to convince Republican senators to hold the line on spending. Ted Stevens, the new chairman of the powerful Appropriations Committee, is not known for tight control of the purse-strings. He is one of the Senate's most successful pork barons, extraordinarily adept at snaring federal funds for his home state of Alaska.

With 11 of the 13 spending bills for the current budget year still to pass, spending decisions will be one of the first signs of the White House's clout. Mr Bush has made it clear that he wants discretionary spending kept within an overall $750-billion target. Mr Stevens used to say that that was not enough. Since the November elections he says he wants to stay within the limit, though many Washington budget-watchers reckon there has been a tacit deal with the White House: the Senate sticks to limits now, but gets more money in a fat pork-laden supplemental spending bill later in the year.

Elsewhere, Mr Bush will find more kindred spirits. The Senate's Environment Committee, long chaired by moderates with ties to the environmental lobby, now has an Oklahoma businessman and friend of the oil industry as its boss. James Inhofe is notoriously sceptical of greens, once calling the government's environmental agency a “Gestapo bureaucracy”. John Warner, new top dog at the Armed Services Committee, is keen both on missile defence and invading Iraq.

Other important committee chairmen often disagree with the White House, however, and are not afraid of doing so publicly. With Jesse Helms's retirement, Richard Lugar has become the new top Republican on the Foreign Relations Committee. A Rhodes scholar and noted foreign-policy expert, Mr Lugar is a strong multilateralist who has been sceptical of many aspects of the administration's policy on Iraq. Mr Bush's political nemesis, John McCain, heads the Commerce Committee. Though Mr McCain shares the Bush team's taste for deregulation, he will hardly be a White House lackey and will be determined to push his own schemes.

The unfinished business of the last Congress, and the upheaval of the sudden shift in the Republican leadership, means that it will take a while for the Senate to get going on a new agenda. With Mr Frist in charge, the broad outlines of that agenda may well mirror White House priorities. But with a small majority and a lot of big egos, the surgeon-senator may have trouble keeping it that way.